When papers are to be discarded, it is desirable to shred them so that others cannot obtain and read them. This is often accomplished by a paper shredder or comminuting device. Typically, one or more documents are fed into a cutting device such as a pair of cutting cylinders. The document is then cut into strips or particles, which exit the shredder and are typically collected in a receptacle.
One problem with shredders occurs when the receptacle fills to capacity. If the receptacle is not emptied, the shredded material continues to accumulate and ultimately spills into the area surrounding the shredder. Besides being unsightly, such a condition may cause an occupational hazard and may be cumbersome to clean up. Another problem that occurs when the receptacle is not emptied in a timely way is that the shredded material may accumulate within the shredder, causing the cutting device to jam and malfunction.
One way to deal with these problems is described in U.S. Pat. No. 5,897,065. This patent describes a mechanical device such as an activating flap or vane to detect when the receptacle is full. Typically, the device is mounted either within the cutting device housing, or within the vicinity of the receptacle. The receptacle is detected as full when the flap or vane is physically moved out of position by the accumulated paper. These types of mechanical detection devices, however, have several drawbacks. First, the shredded material must develop into a grouping that has a density sufficient to activate the flap or vane. When the mechanical device is mounted within the housing, by the time the shredded material grouping achieves such a density, the shredded material may have compacted inside the cutting device to the extent that the cutting device jams. Rectifying such a jam may be problematic. If the activating device is mounted away from the cutting device and near the receptacle, the activating device may be in the way when the receptacle is removed to be emptied.
Accordingly, it would be desirable to have a device that overcomes the disadvantages and limitations described above. The present invention solves the above problem by providing a detecting device to detect the presence of shredded material.